Today we're going to learn how to set up the Go Wireless pH with the LabQuest 2
to do a titration of a strong acid with a strong base. First let's make sure the
Go Wireless pH is charged and turned on. I've charged the Go Wireless electrode
amplifier overnight with its power cable. To turn it on, I press this button right
here. The blinking red light tells us that it's on. My LabQuest 2 is also charged
and on, and updated to the latest software version. It needs to be version 2.4 or
higher to work with the Go Wireless pH. Now that everything's on, I can connect
the Go Wireless pH to my LabQuest 2 via Bluetooth. From the sensors menu on the
LabQuest 2, I'll select Go Wireless Setup. When I first connect to the
Go Wireless pH, it'll read Go Wireless pH. I'll select that and say OK. Now I should
see the pH reading. Before we begin the experiment, let's take a quick tour of the
settings on the Go Wireless pH. First, we're going to want to rename our
Go Wireless pH so we'll know easily which one to connect to in the future.
To do this I'll tap on the big red box and then the Go Wireless menu, sensor info.
Next to the name, where it says Go Wireless pH, I just tap in that field
and rename it whatever I like.
When I'm done renaming, I'll select done. This is where I can also check the
battery level. Select OK to exit. Also in this Go Wireless menu, I can tap on
identify which causes the unit that you're currently connected to, to blink faster.
This is also where you can disconnect properly from the electrode. If you'd like
to calibrate the electrode or change the units you'll also do it from this menu and
just select the appropriate option. Now we're ready to start our titration.
I'm going to be demonstrating this titration with a drop counter.
But if you're using a standard burette, you'll want to connect your
Go Wireless pH and then set up events with entry mode.
This will allow you to enter individual volumes as you dispense them into
the beaker. But again, I'm going to be showing it with a drop counter.
I want to make sure that I remove my pH electrode from its storage solution
and slide it into the slot on the drop counter. Then I'm going to connect the
BTD cable from the drop counter to the LabQuest 2. It goes into the top of the
LabQuest 2 and it'll automatically be identified and the mode will automatically
change to drop counting. I've already set up my 0.1 M NaOH in the burette and my
0.1 M HCl in the beaker. I want to make sure my burette is lined up with the
opening in the drop counter and will go into the beaker. The solution needs to be
stirring. The stir bar, we don't want it to be bumping into the pH electrode.
We also want to make sure that the bulb of the pH electrode is completely submerged
in the solution. Now I'm ready to start taking data. I'll tap on
the collect button on the LabQuest 2, and it's waiting for the drops to come.
So nothing will happen until I start sending drops through the drop counter.
Now I'm going to open my burette and let the drops come in
at about one drop per second.
Once there is a complete titration curve, we can stop data collection.
Then we'll determine the equivalence point by tapping along the graph.
I can also calculate the first and second derivatives. To do that, I'm going to go
over into the table screen. From the table menu, select new calculated column.
I want this to be the first derivative so I'm going to rename the column
first derivative. Now I'm going to select from the equation type menu, scroll all
the way to the bottom and tap on first derivative. And then I'm going to select
OK and it's going to automatically take me to the graph screen where it's graphed the
first derivative for me. Then I can use the statistics analysis after I highlight
the peak to find the volume where the maximum happened. So I can see here,
my volume is 9.45 ml. I can also repeat this process for the second derivative.
The Go Wireless pH is connected via a BNC connection. So you can connect any other
BNC electrode to the Go Wireless electrode amplifier such as our
oxidation reduction potential electrode, our flat pH electrode or third party
electrodes. It's also compatible with iPads via Bluetooth Smart. If you have any
additional questions about the Go Wireless pH electrode or any other chemistry
questions, feel free to go to vernier.com or email chemistry@vernier.com.